The present invention generally relates to a storage apparatus and its power saving method, and in particular relates to a storage apparatus connected to a host system for sending and receiving data to and from the foregoing host system, and to the power saving method of such a storage apparatus.
In recent years, information society is rapidly developing, and the computerization of information is also rapidly advancing. Under these circumstances, the importance of storage apparatuses that store electronic information goods is increasing, and the capacity of such storage apparatuses is ever increasing.
Meanwhile, the operation costs of storage apparatuses are becoming a problem, and the current status is that needs for realizing the power saving of storage apparatuses are increasing.
Thus, a storage apparatus that seeks power saving by spinning down the HDD (Hard Disk Drive) when a fixed standby time is set in the memory of the storage apparatus and there is no access during the foregoing standby time has been proposed (for instance, refer to Japanese Patent Laid-Open Publication No. 2000-100053).
Further, a storage apparatus that seeks power saving by designating a given period of time in the storage apparatus, and switching to a power saving mode or shutting off the power when there is no access during the foregoing designated time has been proposed (for instance, refer to Japanese Patent Laid-Open Publication No. 2000-293314).
Moreover, a storage apparatus that seeks power saving by equipping a power supply device to each storage apparatus case, and turning on or turning off the power of each case has been proposed (for instance, refer to Japanese Patent Laid-Open Publication No. 2004-348876).
Nevertheless, when there is access to a storage apparatus in which the HDD is stopped for power saving, there is a problem in that it takes much time to start the HDD, and there will be no response to the access request, or the response to the access request will be delayed.